Liquid fuel injection pumping apparatus

ABSTRACT

A fuel pumping apparatus for supplying fuel to an internal combustion engine includes a distributor member having a longitudinal bore through which fuel flows to an outlet of the pump. There is also provided a shuttle accommodated in a bore to one end of which fuel is supplied during the initial portion of the injection period and from the other end of which escapes fuel to a low pressure source. The process is reversed on the next injection stroke and the permitted movement of the shuttle is determined by an adjustable stop.

O Umted States Patent 11 1 1111 3,802,808 Kemp Apr. 9, 1974 [54] LIQUID FUEL INJECTION PUMPING 3,633,123 5/l972 Fenne 417/462 APPARATUS FOREIGN PATENTS OR APPLICATIONS Inventor: Kenneth Albert e s p, 952,136 3/1964 Great Britain 417/251 London, England 73 A d h Primary Examiner-William L. Freeh Sslgnee e lrmmg am Attorney, Agent, or Firm--Holman & Stern [2]] Appl. No.1 7 A fuel pumping apparatus for supplying fuel to an internal combustion engine includes a distributor member having a longitudinal bore through which fuel (g1. flows to an Outlet of the p p There is also provided 58] Fie'ld 751 625 3 a shuttle accommodated in a bore to one end of which H fuel is supplied during the initial portion of the injec- [56] References Cited tion period and from the other end of which escapes fuel to a low pressure source. The process is reversed UNITED STATES PATENTS on the next injection stroke and the permitted movegj ggg glikin ment of the shuttle'is determined by an adjustable l emp I 3,498,226 3/1970 Mowbray 417/253 Stop 3,058.425 lO/l962 Evans 417/252 3 Claims, 2 Drawing Figures LIQUID FUEL INJECTION PUMPING APPARATUS This invention relates to liquid fuel injection pumping apparatus for supplying fuel to an internal combustion engine and of the kind comprising in combination, an injection pump having an outlet communicating with a passage communicating in turn and during successive delivery strokes of the injection pump with a plurality of outlet ports formed in a body mounting the distributor member and communicating in use, with the injection nozzles respectively of an associated engine, and means for supplying fuel to the injection pump during an inlet stroke thereof.

With such apparatus it is necessary to be able to control the maximum amount of fuel which can be supplied at each delivery stroke of the pump and the object of the present invention is to provide such an apparatus in a simple and convenient form.

According to the invention an apparatus of the kind specified comprises a shuttle slidable within a bore formed in the body, port means whereby the opposite ends of said bore are placed in communication alternately with said passage during successive delivery strokes of the injection pump, further port means through which said ends of the bore can be placed in communication alternately with a source at low pressure during successive delivery strokes of the injection pump and means for controlling the extent of movement of the shuttle, the arrangement being such that during one delivery stroke said passage is in communication with one end of said bore so that at the start of the delivery stroke the shuttle is moved away from said one end of the bore, fuel being allowed to escape from the other end of the bore, and at the next delivery stroke the passage communicates with the other end of the bore so that the shuttle is moved in the opposite direction and fuel escapes from said one end of the bore to said source.

One example of a pumping apparatus in accordance with the invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is a sectional side elevation of the apparatus and taken on the line YY of FIG. 2, and

FIG. 2 is a sectional end elevation taken on the line X--X of FIG. 1.

Referring to the drawings there is provided a two body part in which is mounted a rotary cylindrical distributor member 11. The distributor member 11 is coupled by means of a shaft 12 to an internal combustion engine so that it rotates in synchronism therewith.

The distributor member is provided with a transversely extending bore 13 in which are mounted a pair of pumping plungers 14 which are moved inwardly as the distributor member rotates, by means of cam lobes formed on the internal periphery of an annular cam ters in turn with a plurality of outlet ports 20 formed in the body part and communicating respectively with the injection nozzles of an associated engine.

The longitudinal passage 18 also communicates with a plurality in this case 4, of inlet passages 21, which extend to the periphery of the distributor member and which register in turn during the inlet strokes of the injection pump, with an inlet port 22 formed in the body' part. The port 22 communicates with a fuel supply gallery 23 by way of an adjustable throttle member 24. The throttle member in use, is connected to a governor which is responsive to the speed at which the associated engine is operating. The fuel supply gallery 23 communicates with the outlet of a feed pump 25 and in the position shown, the port 22 is in register with an inlet passage 21 so that fuel is flowing into the passage 18 to effect separation of the plungers 14. As the distributor member continues to rotate a passage 21 is moved out of register with the port 22 and the passage 19 moves into register with a port 20. When this has occurred inward movement of the plungers due to the action of the cam lobes effects delivery of fuel to the associated engme.

The amount of fuel which is supplied to the engine is controlled by the setting of the throttle member 24 however, it is essential to ensure that the maximum quantity of fuel which is supplied to the engine is strictly controlled in order to avoid exceeding the allowed quantity of smoke in the engine exhaust. For this purpose there is provided in the body part a bore 26 in which is mounted a shuttle 27. The axis of the bore extends at right angles to the axis of rotation of the distributor member. One end of the bore 26 is closed by a fixed stop 28 and the other end of the bore is closed by a plug 29 having a contoured face presented to the shuttle 27. The angular setting of the plug 29 is adjustable from the exterior of the apparatus and the form of the face presented to the shuttle is such that the extent of movement allowed to the shuttle before it contacts the face of the plug 29 depends upon the angular setting of the plug.

The opposite ends of the bore 26 communicate with ports 31,32 which break out onto the periphery of the distributor member. Moreover, formed on the distributor member are two pairs of axial slots 33, 34 the slots of each pair of slots being diametrically disposed. The slots 34 communicate with a pair of the inlet passages 21 whilst the slots 33 extend to a circumferential groove formed on the distributor and which cummunicates with the supply gallery 23. In other words the slots 33 communicate with a drain or source of fuel at low pressure.

In use, one of the slots 34 communicates with either of the ports 31, 32 and. one of the slots 33 communicates with the other of these ports during the time when the plungers 14 are moving inwardly under'the action of the cam lobe's. As shown in FIG. 2 of the drawings, a slot 34 communicates with the port 32 and a slot 33 communicates with the port 31. FIG. 2 shows the position of the various parts of the apparatus at the start of a pumping period and it will be seen that during inward movement of the plungers 14 fuel will be displaced from the passage 18 via a slot 34 and the port 32 into the end of the bore containing the plug 29. Movement of the shuttle 26 towards the stop 28 will therefore take place and the fuel will be displaced from the end of the bore containing the stop 28 by way of the port 31 and a slot 33. When the shuttle 27 strikes the stop 28 further flow of fuel will cease and the remaining quantity of fuel displaced by the plungers 14 will flow to the associated engine. At the next delivery stroke following a filling stroke, a slot 34 will register with the port 31 and a slot 33 will be in register with the port 32 so that as fuel is displaced by the injection'pump fuel will flow into the end of the bore containing the stop and movement of the shuttle will take place in the direction towards the plug 29a. When the shuttle contacts the stop 29, the flow of fuel will cease and the remaining quantity of fuel displaced by the plungers 14 will flow to the associated engine. In this manner the maximum quantity of fuel which can be delivered to the engine can be varied by adjusting the angular setting of the plug 29. Moreover, the plug 29 can be adjusted so that an excess of fuel can be supplied to theengine for starting purposes. In this instance the shuttle 27 will be restrained from moving within its bore.

The particular apparatus shown is for supplying fuel to a four cylinder compression ignition engine however, it will beappreciated that slight modification only is required to enable the apparatus to supply fuel to an engine having an odd number of cylinders.

I claim:

1. A liquid fuel injection pumping apparatus for supplying fuel to an internal combustion engine comprising in combination, a pump body, an injection pump located within the body, a distributor member rotatably mounted in the body, the injection pump and distributor member being driven in timed relationship with the associated engine, a passage formed in the distributor member and communicating with the injection pump, a plurality of outlet ports formed in the body, said passage registering in turn with said outlet ports during successive delivery strokes of the injection pump, the outlet ports in use, communicating respectively with the injection nozzles of the associated engine, means for supplying fuel to the injection pump during the filling strokes of the injection pump, a bore formed in the pump body, a shuttle slidable within said bore, a pair of further passages communicating with the opposite ends of said bore, said further passages opening onto the distributor member at angularly spaced points, first groove means on the distributor member communicating with said passage whereby said further passages in turn are placed in communication with said passage during successive delivery strokes of the injection pump, second groove means on the distributor member, said second groove means communicating with a source of fuel at low pressure, said second groove means registering with said further passages in turn during successive delivery strokes of the injection pump and means for controlling the extent of movement of the shuttle, the arrangement being such that during one delivery stroke said passage is in communication with one end of said bore through one of the further passages and the first groove means so that at the start of the delivery stroke the shuttle is moved away from said one end of the bore, fuel being allowed to escape from the other end of the bore through the other of said further passages and the second groove means, and at the next delivery stroke the passage communicates with the other end of the bore so that the shuttle is moved in the opposite direction and fuel escapes from said one end of the bore to said source.

2. An apparatus as claimed in claim l'in which said means comprises a fixed stop at one end of the bore and an adjustable stop at the other end of the bore.

3. An apparatus as claimed in claim 1 in which the axis of the bore extends at right angles to the axis of rotation of the distributor member.

t t i 

1. A liquid fuel injection pumping apparatus for supplying fuel to an internal combustion engine comprising in combination, a pump body, an injection pump located within the body, a distributor member rotatably mounted in the body, the injection pump and distributor member being driven in timed relationship with the associated engine, a passage formed in the distributor member and communicating with the injection pump, a plurality of outlet ports formed in the body, said passage registering in turn with said outlet ports during successive delivery strokes of the injection pump, the outlet ports in use, communicating respectively with the injection nozzles of the associated engine, means for supplying fuel to the injection pump during the filling strokes of the injection pump, a bore formed in the pump body, a shuttle slidable within said bore, a pair of further passages communicating with the opposite ends of said bore, said further passages opening onto the distributor member at angularly spaced points, first groove means on the distributor member communicating with said passage whereby said further passages in turn are placed in communication with said passage during successive delivery strokes of the injection pump, second groove means on the distributor member, said second groove means communicating with a source of fuel at low pressure, said second groove means registering with said further passages in turn during successive delivery strokes of the injection pump and means for controlling the extent of movement of the shuttle, the arrangement being such that during one delivery stroke said passage is in communication with one end of said bore through one of the further passages and the first groove means so that at the start of the delivery stroke the shuttle is moved away from said one end of the bore, fuel being allowed to escape from the other end of the bore through the other of said further passages and the second groove means, and at the next delivery stroke the passage communicates with the other end of the bore so that the shuttle is moved in the opposite direction and fuel escapes from said one end of the bore to said source.
 2. An apparatus as claimed in claim 1 in which said means comprises a fixed stop at one end of the bore and an adjustable stop at the other end of the bore.
 3. An apparatus as claimed in claim 1 in which the axis of the bore extends at right angles to the axis of rotation of the distributor member. 